Getter flashing device



July 15, 195 8 H e. A. COLTRIN 2,843,445

GETTER FLASHING DEVICE Filed Jan. 4, 1956 I 2 Sheets-Sheet 2 l I I mum Q1 INVENTOR GENE A. COLTRIN ATTO United States Patent O GETTER FLASHINGDEVICE Gene A. Coltrin, Hollidaysburg, Pa., assignor to SylvaniaElectric Products Inc., a corporation of Massachusetts ApplicationJanuary 4, 1956, SerialNo. 557,308

Claims. (Cl. 316-'30) This invention relates to getter flashing devicesand methods of getter flashing.

Prior to this invention two common methods of flashing the getter inelectronic tubes had been used. In one, the getter is flashed during theexhaust cycle and immediately after bombardment of interior elementswith high frequency currents to heat them to drive off occluded gasesand immediately after excess filament heating to properly condition thecathode. Any imperfection in the vacuum system of the exhaust machinewill allow the gas pressure in the tube to increase between the time thetube is flashed and the time when it is finally sealed; in addition, thedescribed method does not provide sufficient active gettering materialat the time the bulb is tipped since some of it had been exhausted priorto tipping off of the bulb; also gases liberated from the molten glassare left free in the tube and adversely affect initial characteristicsof the tube and tube life.

The other common method used in tube manufacture is to flash the getterafter the tube is tipped off and cooled. This method reduces the gascontent, but since the mount structure is cold, getter material easilycondenses on the insulating spacers in the tube and creates leakagepaths between electrodes. In addition, some gases which were left in thetube after tipping-off may be adsorbed into the tube parts as they coolcompletely and these gases will not be readily available to combine withthe active getter material when the tube is flashed, but may besubsequently liberated when the tube is aged or put into use.

The main object of this invention is to provide a means to flash thegetter during and immediately following the tipping off operation.During these times very little of the getter material is exhausted fromthe tube and, since all the parts are hot, the getter will readilycombine with the gases liberated from the glass and with such residualgases as are left due to incomplete exhaust. This flashing occurring ata time when the interior tube parts are still maintained at a hightemperature will result in marked decrease in condensation on theinsulators of getter material. The bulb which is then exposed to theambient atmosphere will be cooler than the interior portions of thetube, such as the insulators, and will receive the getter condensationrather than the hot mount within the bulb. A further object of theinvention is to provide for a method of tube getter flashing which shallresult in retaining within the tube most of the getter materialoriginally in the tube but yet result in little, if any, deposits ofgetter material on the mount structure within the tube.

Other objects will become apparent after considering the followingspecification and claims in conjunction with the accompanying drawingsin which Fig. l is a side elevation of the flashing device, showing thetip-off station, a flasher coil surrounding a tube, and transfermechanism to remove a tube from the tip-off station.

Fig. 2 is a view similar to Fig. 1 but showing the transfer mechanism ina shifted position of parts ready to drop a completed tube onto a chute,the flasher coil being tilted out of the path of falling movement o fthe bulb.

Fig. 3 is a plan view of the flasher and transfer mechanism with partsin the position of Fig. 1.

Fig. 4 is a view similar to Fig. 1 but from the opposite side of thestructure, and

Fig. 5 is a view looking to the right at Fig. 4 but with the bombardercoil broken away.

Now referring to the drawings in greater detail, at 10 there isindicated a table on which is fixedly mounted a standard 12 to which isattached a webbed bracket 14 at the upper end of which is a bearing 16within which is journaled a stub shaft 18.

Aflixed to an enlarged portion of the shaft 18, see Fig. 5, as by a pin20 is a tube transfer arm 22 to which is secured an angled extension 24supporting articulated jaws 26 and 28 pivoted at 30 on the extension.The two jaws are normally resiliently held together by a spring 32tensioned between pins 34 carried by the jaws. One of the articulatedjaws, jaw 28, is provided with an operating arm 36 against which may bethrust an operating rod 38 pivoted to a bell crank lever 40 via a link42. The bell crank lever is pivotally mounted as by the pin 20 in a slotin the end of shaft 18 and is normally held against an operating wearplate 44 by a spring 46 coiled about the rod 38 and reacting between oneof a pair of bearings 48 for the rod and a stop 50 fixed on the rod. Thewear plate is shaped to enable the plate to swing past the bearing 16and arm 22 but yet to provide for continuous engagement of anantifriction roller 51 on the free end of bell crank lever with theplate as the jaws are swung around the axis of shaft 18. The plate 44 ismounted on a free end of a bell crank lever 52 rotatable on a pivot 54in the bracket 14. The other end of the lever 52 is connected to a-link56 which in turn is connected to and operated by a lever 58 whosemovement is controlled by a cam 60 mounted on a cam shaft 62 on themachine. The cam shaft is synchronized for movement with a turret 64supporting exhaust ports 66, as is conventional in the art. When theplate 44 is oscillated about the pivot 54, the rod 38 will effect theopening of the jaws 26, 28 and release any tube held by the jaws toallow it to drop upon a carry off chute 67. To rotate the jaws about theaxis of shaft 18, an arm 68 having a collar 70 pinned to the shaft 18 isconnected to a link 72 operated at .its lower end by a pivotallyconnected lever 74 in turn operated by a cam 76 fixed on the cam shaft62. Oscillation of shaft 18 will therefore move the jaws between thedown-position shown in Figs. 1 and 3 and the up-position shown in Figs.2, 4, and 5. During this oscillation of shaft 18 the bell crank 40 willoscillate therewith with its antifriction roller 51 at all times opposedto the plate 44. The cams 60 and 76 are so contoured that the plate 44will be oscillated toward the free end of the bell crank when the jawsare in the fully raised position, thereby operating the jaws andreleasing the tube when in that position. The cam 60 also functions toswing the plate 44 to open the jaws before the jaws have been swung downover a bulb on the exhaust port 66 of the turret 64 and to retract theplate to allow the jaws to close on the bulb before the jaws swingupward. During the sealing 01f operation of the tubulation eifected bythe fires from burners 78 held on the ends of an adjustable bar 79, ithas been customary to draw the bulb upwardly while the tubulation isheld tight in the exhaust port. For this purpose there is. provided acup 80 at a level below the bottom of the bulb during turret indexingand open at its side (-not shown) to enable the turret borne tube andtubulation to index into position relative to the cup. The cup ismounted on a rod 82 slidable in a sleeve 84, the rod being resilientlyheld in telescoped relation with the sleeve by a spring 86 tensionedbetween the two. The sleeve is mounted on a bracket 88 on the upper endof a post 90 vertically reeiprocatable in the standard 12. At the lowerend of the post is a link 92 connected to a lever 94 operated by a camtrack 96 in a cam 98 fixed onthe shaft 62. To prevent rotation of thebracket 88, the same has fixed thereto a guide bar 100 slidable in aslot between lugs 102 on the standard 12. During the tipping-ofl?operation, the cup engages beneath the bulb while flames are applied tothe exhaust tubulation and while the bulb is still under exhaust. Thebracket 88 rises to cause the cup to engage the bulb, the spring 86 inthe meantime being stretched and put under further tension sinceinitially the bulb does not move upward with the bracket. Eventually thetubulation softens sufiicie'ntly to allow the spring 86 to contract andto quickly assist in separation of the tubulation sections above andbelow the heated areas, the complete separation being effected by thecontinued rise of the bracket 88.

So far the exhausting and tip-01f structure and operation have beendescribed. Now attention is directed to the associated getter flashingstructure and operation.

Mounted on the arm 68 is a bent bar 104, the same being aflixed to thearm 68 as by screws 106. To this bar is aflixed a second wider bar 108fixedly carrying at its free extremity one leaf of a two-leaved hinge110, the other leaf being fixed to a small rectangular plate or platform112. At an outer end of this platform is a cam follower roller 114 andat the other end is an insulating block 116. The roller 114, as theshaft 18 is oscillated from the position in Fig. 1 to the position inFig. 2, will engage a cam iron 118 fixed on the bearing 16 and pivot theplatform 112 and the block 116 to the position shown in Fig. 2. Theblock 116 supports the tail ends of a flasher induction coil 1 20,conventionally made of hollow brass tubing through which there is acirculation of cooling fluid with conductive insulated hollow flexibleleads 122 conducting said fluid as well as high frequency current to andfrom the coil. The cam 118 is so positioned that the platform will tiltthe coil 120 ufliciently out of the way of the tube held by the jaws topermit the tube unhindered movement onto the chute 67 when the jaws 26,28 release the tube. The weight of the coil 120 and appurtenances willbias the platform to the position of Fig. l in the down position of barmeans 104, 108. The cam 76 is so mounted on shaft 62 that it will bringthe bombarder coil over the dome of the bulb in concentric relation withthe axis of the bulb and the open jaws around the bulb just as the seat80 rises, the coil being then directly in line with and above the jaws.The cam 60 then permits closure of the jaws on the bulb. Current to thecoil is under control of a switch 124 operated by cam 126 on the shaft62 and is supplied to the coil substantially from the time that the jawsand coil reach the position shown in Fig. 1 until the coil reaches theposition shown in Fig. 2. Thus heating of the getter material isinitiated while the tube is still under exhaust with flashing takingplace just immediately prior to tipping off, and heating of the gettersupport continues during substantially all of the time until the coil isdisplaced to the position shown in Fig. 2. All of the interior parts ofthe tube during and immediately after flashing are still hot due toprevious bombardment of electrode elements in the tube and excessfilament heating as explained previously. But the bulb, due to exposureto the ambient atmosphere, is much cooler than the interior contents.Therefore getter material will tend to condense on the interior of thebulb rather than on the insulators or electrodes within the bulb. Thusinterelectrode leakage due to getter deposi tion is materially reduced,while yet little, if any, of the getter material is exhausted from thetube prior to tip-off.

Although the preferred embodiment discloses a flasher coil movable withand relative to a transfer means, it shouldbe obvious that other flashermeans Within the scope of the claims may be utilized. So, too, other 4transfer mechanism than that preferred and shown may be utilized, solong as they fall within the scope of the appended claims. The mechanismherein disclosed is exemplary, the invention being defined in theappended claims.

What is claimed is:

1. In mechanism for finishing tubes involving tippingoff the same andflashing the getter therein, the combination comprising: a tip-offmechanism, a carry-off device, a device for transferring a tube fromsaid tip-off mechanism to said carry-off device a flasher device,movable with the transfer device, and means operative immediately beforesaid tipping-off and during operation of said transfer device toenergize the flasher device to flash the getter within the tube.

2. In mechanism for finishing tubes involving tippingoff the same andflashing the getter therein, the combination comprising: a tip-offmechanism, a carry-off device, a device for transferring a tube fromsaid tip-ofl mechanism to said carry-oft device, a flasher devicemounted on and movable with the transfer device, and means operativeimmediately before said tipping off and during operation of saidtransfer device to energize the flasher device to flash the getterwithin the tube.

3. In mechanism for finishing tubes involving tippingoff the same andflashing the getter therein, the combination comprising: a tip-offmechanism, a carry-off device, a device for transferring a tube fromsaid tip-off mechanism to said carry-off device, a flasher devicemovably mounted on and movable with the transfer device, means operativeimmediately before said tipping-off and during operation of saidtransfer device to energize the flasher device to flash the getterwithin the tube, and means to move the flasher device relative to thetransfer device and away from the tube at the end of operation of thetransfer device.

4. In mechanism for finishing tubes involving tippingofl the same andflashing the getter, the combination comprising: a tip-off mechanism, acarry-off device, a transfer device for transporting a tube from thetip-off mechanism to the carry-off device, said transfer deviceincluding a pivoted arm with bulb engaging jaws at the free end of thearm, a bar movable with and parallel to the arm and, a platform pivotedto an end of the bar, a cam follower on the platform, a fixed camengaged by said follower when the bar is pivoted, and a flasher coilfixed to said bar, said coil in one position of the am being directlyaligned with the jaws.

5. In mechanism for finishing tubes involving tippingoff the same andflashing the getter, the combination comprising: a tip-off mechanism, acarry-off device, a transfer device for transporting a tube from thetip-off mechanism to the carry-off device, said transfer deviceincluding a pivoted arm with bulb engaging jaws at the free end of thearm, .bar'm'eans pivoted coaxially with the arm and provided at its freeend with a pivoted platform with said platform having a portionextending over the bar means and a second portion extending beyond thebar means, a cam follower on said second portion, a fixed cam engageableby said follower, and a flasher coil fixedly carried by said platform,said coil being concentric with the axis of a tube held by said jawswhen the first portion of the platform rests on the bar means and beingout of the way of the tube when the follower engages the fixed cam.

References Cited in the file of this patent UNITED STATES PATENTS1,028,636 Thatcher June 4, 1912 1,461,155 Madden et a1 July 10, 19231,596,733 Higgins Aug. 17, 1926 1,626,679 Kelly May 3, 1927 1,894,948Espe et a1 Jan. 24, 1933 2,006,771 Kayko et al. July 2, 1935 2,673,784Snyder Mar. 30, 1954

